Engine/Transmission (1998.5 - 2002) Need Help Diagnosing Accelerator Problem

[DCrabbs]

On four occasions traveling from Oregon to Ohio, I completely lost my accelerator. Each time I was in the process of exiting an interstate highway after traveling along with no indication of trouble. I would disengage the cruise control, slow down (sometimes activating the exhaust brake - sometimes not), and pull off unto an exit ramp. When I would attempt to go on, the accelerator would not work. The engine would idle normally and the check engine light would be on. In each case, I was able to pull off on the shoulder and continue on to a safe area with the engine at idle, but the foot feed had no effect. I discovered that, if I shut the truck off and restarted it, the accelerator would work normally, but the check engine light would remain on for a period of time. The first time the check engine light went off about 30 minutes later. In each of the other three cases, the check engine light remained on until the truck had been shut off for a period of time.



I plan on taking it in to a dealer this next week, but sure am curious what kind of gremlin is loose under my hood.



Any similar experiences or bright ideas?



Dean

 

[Turbo Tim 1]

Turn your key on and off three times, the final time leaving it on and tell us what codes appear in the odometer display.

 

[BSeitz]

Sounds like it's your throttle position sensor, or as some dealerships refer to them as APPS sensor (accelerator pedal position sensor). If it goes to idle for no reason, its the sensor going into some kind of limp mode. My check engine light went on and off three times a couple of weeks ago. The code for the TPS/APPS is PO122. Mine never went into limp mode like yours, but they can fail in different ways, so i'm told. My truck has 52,000 miles and they replaced it under warranty. If its out of warranty, I believe the sensor is around 400 bucks. It's a DODGE part only. Cant get it at CUMMINS. Good luck.

 

[DCrabbs]

The codes that come up are:



P 0500

P 1693

P 0121



Dean

 

[Turbo Tim 1]

P0121 Accelerator Pedal Position Sensor Signal Volts Do Not Agree w/Idle Validation Signal



This is the one that is your problem, I did a search on "p0121" and came up with a bunch of information.

 

[BSeitz]

1. P0121 = APPS VOLTAGE INPUT BELOW THE MINIMUM ACCEPTABLE VOLTAGE. 2. P0121 =TPS VOLTAGE DOES NOT AGREE WITH MAP SENSOR(MANIFOLD ABSOLUTE PRESSURE), SIGNAL DOES NOT CORRELATE TO MAP SENSOR SIGNAL. 3. P0500 =NO VEHICLE SPEED SENSOR SIGNAL DETECTED DURING ROAD LOAD CONDITIONS. 4. P0500 =A VEHICLE SPEED SIGNAL WAS NOT DETECTED. 6. P1693= A FAULT HAS BEEN GENERATED IN THE COMPANION ENGINE CONTROL MODULE. 7. P1693= A COMPANION DTC WAS SET IN BOTH ECM AND PCM. THE P1693 CODES ARE SOMEWHAT GENERIC, YOU NEED A SCAN TOOL TO TELL YOU THE PROBLEM FURTHER. ALL THESE CODE DESCRIPTIONS CAME RIGHT OUT OF MY SHOP MANUALS, I DON'T KNOW WHY THEIR ARE TWO EXPLANATIONS FOR EACH. HOPE THIS HELPS. I STILL THINK ITS YOUR TPS/APPS SENSOR.

 

[DCrabbs]

Thanks guys! Subscribing to the TDR is money well spent when you own a CTD!



BSeitz - You said yours was replaced at 52000 miles under waranty. Was that the regular warranty or an extended one?



I'll post again when it's fixed.



Dean

 

[BSeitz]

DCRABBS I have the extended warranty 7/100,000 miles. The part cost me $100 for the deductible.

 

[DCrabbs]

Problem solved! It was the APPS. The dealer ran the appropriate diagnotics and confirmed the problem. They had to order the part, but got it in overnight. The best part was, they covered it under the regular 100,000 mile drivetrain warranty. The sensor alone is a $450. 00 part!



Dean